The invention relates to an electrical valve used to control flow through a hydraulic supply line and, more particularly, to an actuator for an electrically-controlled hydraulic diaphragm valve.
It is desirable to operate valves in some irrigation systems automatically. The automatic operation requires a pilot device to open and close a port to the valve control chamber to allow water to enter and leave the control chamber. This can be done with a three-way solenoid valve or motorized valve. In one version, an electro-mechanical mechanism moves a piece that can open a port that allows water to enter the control chamber of the valve and then close the port to allow water to leave the control chamber.
With reference to FIG. 1, when the motor is energized, a pinion gear (not shown) on the motor shaft spins and rotates a ring gear. A cam guide on the ring gear guides the pin on the cam, thus rotating the cam. The cam pushes on the side of a rocker, which results in downward movement of the pin. The pin then presses down on a diaphragm, squeezing it against the port and sealing off the flow of water. When the motor is energized in the opposite direction, the mechanism reverses, and the other port is sealed. This allows water to enter from the previously sealed port.
A valve of this type is described in U.S. Pat. No. 6,394,412, the contents of which are hereby incorporated by reference.
In use, existing motorized valves are lacking robustness and are prone to failure if dropped or operated beyond 30,000 cycles. When the structure fails, the motor shifts and the gear train no longer functions properly. Thus, the existing valves fail to seal off the ports, and fluid leaks past the seals. The internal structure can also fail when the existing valves are dropped. Additionally, existing motorized valves are rated for 150 psig operating pressure, while many applications require 175 psig operating pressure. Still further, when the existing motorized valves have been left non-operating for a period of time, for example over winter, the valve can end up in an in-between state, where it is neither open nor closed. This requires a cycling of the valve prior to the start of irrigation to set it in the correct state. Existing motorized valves also lack provisions to protect the wires that connect the valve with a power source. Finally, the existing mounting schemes may not work well with all valves.